Kane Kennedy, 20, has admitted to grabbing his son, Oskar Jobey-Kennedy, by his testicles, pinching or twisting them, sticking his finger down his throat and eventually smothering him to death.

Paramedics had responded to a call and found Oskar unresponsive. He was rushed to Royal Lancaster Infirmary, where he was pronounced dead shortly after.

Post-mortem examination results indicated that the child suffered multiple non-accidental injuries and had a total of 13 marks on his face and neck. They also found bruising on the baby’s testicles.

The court heard that Kennedy and Oskar’s mother, Tia Jobey, 19, had been arguing about Kennedy’s cannabis use two months prior to the child’s death.

Jobey told authorities Kennedy would become “stressy” when he could not smoke, and that it made him “paranoid about everything.”

The court heard about Facebook messages exchanged between the couple, BBC reported. In one message, Jobey wrote:

“I’m trying to make sure Oskar is happy and safe and while you are addicted to weed and violent and abusive he’s not safe at all.

You throw him around like a toy, suffocate him, stick your finger down his … throat. And he’s always in the middle of our arguments and fights.”

Jobey admitted her relationship with Kennedy was not good and that she should have left him, but said she stayed with him because she feared being alone.

Jobey’s attorney, Stuart Denney, said the teen mother had fallen “head over heels in love” with Kennedy when she was just 16 years old. Denney added that his client’s affections for Kennedy “blinded her to reality.”

Kennedy initially denied murdering his son and tried blaming the death on Jobey. The jury did not believe his story.

Jobey pleaded guilty to causing or allowing the death of a child at an earlier hearing. She was sentenced to 30 months in a young offender institution.